DESCRIPTION: (Applicant's Abstract) Inhalants are the only major class of abused drugs that are not regulated in the United States. Inhalant abuse is on the rise, particularly among young adolescents, and little is known of the consequences of this behavior. Because of the unrestricted availability of inhalants, often as common household items, there is growing concern that they may serve as a 'gateway drug' for other forms of drug abuse. Given the large number of inhalants available, it is imperative to explore ways of identifying those with abuse potential. Although methods have been developed to screen for abuse potential, they have not been applied to inhalants. Presumably this is because of the difficulties in arranging inhalation as a route of administration in experimental animals. Recent advances in vehicle preparations for inhalant-like anesthetics such as propofol and isoflurane provide a means to apply intravenous self-administration techniques to the study of the abuse potential of inhalants. Promising pilot data appears to confirm that these agents support behavior that leads to their delivery. The initial phases of this project are designed to screen a wide range of inhalants for behavioral activity. The next phase of the project will directly determine the abuse potential of behaviorally active agents using self-administration techniques. The initial phase will rank order the abuse potential of compounds actively self-administered using two techniques that have been successfully applied to assess the abuse potential of other types of agents. If time permits, this project will also determine the effects of drug pretreatment on inhalant-maintained performances, in order to more fully evaluate their ability to alter measures of reinforcing efficacy of inhalants. In addition to the direct benefits of rank ordering the extent to which various inhalants are likely to be abused, this project characterizes a new class of drugs of abuse, and as such, potentially adds to our knowledge of factors associate with drug abuse in general.